Plasma processing apparatus and microwave output device

ABSTRACT

A plasma processing apparatus includes: a high voltage power supply for supplying a high voltage power to a magnetron; and a detector for detecting a microwave output from the magnetron, wherein based on a result of comparing a signal, which is obtained by adding an output from the detector to an AC component of a current detected from an output of the high voltage power supply, with a setting value of the output of the high voltage power supply, the output of the high voltage power supply is adjusted.

BACKGROUND OF THE INVENTION

The present invention relates to a plasma processing apparatus thatprocesses a substrate-like material, such as a semiconductor wafer,arranged in a processing chamber inside a vacuum container by plasmathat is formed using microwave supplied into this processing chamber,and to a device that outputs microwave supplied to a processing chamber.In particular, the present invention relates to a plasma processingapparatus and a microwave output device that form microwave using anoscillator, such as a magnetron, and supply the same to a processingchamber.

In the plasma processing apparatus for manufacturing a semiconductordevice by processing a substrate-like sample, such as a semiconductorwafer, using plasma, a stable and high precision output of microwave isrequired. A magnetron is conventionally used for generation of suchmicrowave.

A device for outputting such microwave typically includes a magnetron, afilament power supply for heating a filament of the magnetron, a highvoltage power supply for oscillating and exciting the magnetron.However, the output efficiency of a magnetron differs depending on itsuse condition and furthermore a magnetron also has an individualdifference, and therefore in order to obtain a high precision and stableoutput, a detector for detecting a microwave output is provided on theoutput side of a magnetron and a microwave output monitor signalobtained by this detector is fed back to a high voltage power supply tocontrol the output of the high voltage power supply, thereby adjustingthe magnitude of the output to within a predetermined value range.

As the examples of such a related art, the disclosures inJP-A-01-232727, JP-A-2000-294396, JP-A-2011-103270, and TECHNICAL REPORTOF IEICE SPS 2004-18(2005-02) are known. For example, JP-A-01-232727discloses a technique for feeding back a signal obtained by monitoringthe output of microwave to a high voltage power supply and controllingthe output of this high voltage power supply.

JP-A-2000-294396 discloses a technique, wherein in order to realize ahigh speed response in automatic matching of microwave, a monitor signalis fed back to a high voltage power supply to control the output of thehigh voltage power supply, and on the other hand when a reflectionelectric power is high, an anode current monitor signal is temporarilyfed back to control the output of the high voltage power supply.JP-A-2011-103270 discloses a technique for detecting the moding of amagnetron from a signal, which is obtained by monitoring an anodecurrent, and controlling the output of a high voltage power supply.TECHNICAL REPORT OF IEICE SPS 2004-18(2005-02) describes an outputfluctuation called a parasitic oscillation.

SUMMARY OF THE INVENTION

The above-described related arts do not fully take into considerationthe following points, and thus pose a problem. That is, as the firstproblem to be solved in the related arts, the response to detect theoutput of microwave is poor and thus the output of microwave willfluctuate with respect to a disturbance having a cycle shorter than thisresponse speed or than a lapse time required for detection.

For example, for a ripple that could not be completely removed in aprimary rectification smoothing circuit of a high voltage power supply,when a time lag in the response of a detector for detecting the outputof microwave is larger than the cycle of the ripple and the responsespeed is too slow, the ripple cannot be removed and this ripple will beoutput as the ripple in the microwave output as it is. In order toremove or suppress this ripple, the response of the detector of theoutput of microwave needs to be improved or a large coil or condenserneeds to be used for the primary rectification smoothing circuit.However, in the latter case, the manufacturing cost of the detector orthe volume and the mounting area of the high voltage power supply willincrease. Moreover, even if the ripple is suppressed using a large coilor condenser, there is no measure to suppress a fluctuation exceedingthe response speed of the detector, and therefore it is difficult tosubstantially reduce the fluctuation in the microwave output caused bythe ripple.

As the second problem to be solved, an abnormal oscillation of amagnetron called “moding”, which is a conventional problem to be solved,needs to be suppressed. When the moding occurs, a short lasting andsteep current will flow in a magnetron, which might damage the magnetronand a high voltage power supply.

As the third problem to be solved, an output fluctuation of a magnetroncalled a “parasitic oscillation” needs to be suppressed. This outputfluctuation is the output fluctuation caused by the magnetron itself. Inthe related art as in JP-A-01-232727, this output fluctuation affectsthe detection result of a detector of the output of microwave, and basedon the output result from the detector the output of microwave isadjusted. Such a related art poses a problem that the more accuratelythe detection is performed, the more the output of microwave willfluctuate.

The present invention has been made in view of the above circumstancesand provides a plasma processing apparatus and a microwave output devicecapable of accurately stabilizing the output of microwave and improvingthe processing accuracy.

The above-described purpose can be achieved by a plasma processingapparatus that forms plasma inside a processing chamber using microwaveformed by a magnetron and processes a wafer arranged inside theprocessing chamber, or a microwave output device used for the plasmaprocessing apparatus, the plasma processing apparatus or the microwaveoutput device including: a high voltage power supply for supplying ahigh voltage power to the magnetron; and a detector for detecting amicrowave output from the magnetron, wherein based on a result ofcomparing a signal, which is obtained by adding an output from thedetector to an AC component of a current detected from an output of thehigh voltage power supply, with a setting value of the output of thehigh voltage power supply, the output of the high voltage power supplyis adjusted.

With the microwave plasma processing apparatus and the microwave outputdevice of the present invention, the fluctuation with respect to aripple or other disturbance can be reduced and the damage to a magnetronand/or a high voltage power supply caused by the moding of the magnetroncan be reduced. Moreover, the occurrence of moding and a parasiticoscillation can be detected and reported to a user or a host controller,and furthermore the adequate maintenance of a magnetron and a highvoltage power supply can be performed and/or the processing at theoccurrence of a parasitic oscillation can be stopped.

Other objects, features and advantages of the invention will becomeapparent from the following description of the embodiments of theinvention taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a vertical cross-sectional view schematically showing anoutline of the configuration of a plasma processing apparatus accordingto an embodiment of the present invention.

FIG. 2 is a block diagram schematically showing the configuration of amicrowave output device of the plasma processing apparatus shown in FIG.1.

FIG. 3 is a block diagram showing a variant of the microwave outputdevice according to the embodiment shown in FIG. 1.

FIG. 4A is a graph showing an example of an anode current of a microwaveoutput device according to a related art.

FIG. 4B is a graph showing an example of an anode current of themicrowave output device according to the embodiment shown in FIG. 2.

FIG. 5 is a view showing an example of the anode current at theoccurrence of the moding of a magnetron.

FIG. 6 is a circuit diagram showing the configuration of an AC componentdetection circuit 16 of the microwave output device according to theembodiment shown in FIG. 2.

FIG. 7 is a circuit diagram showing the configuration of a detectioncircuit 17 of the microwave output device according to the embodimentshown in FIG. 3.

FIG. 8 is a block diagram schematically showing another variant of themicrowave output device according to the embodiment shown in FIG. 2.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Hereinafter, embodiments of the present invention will be described withreference to the accompanying drawings.

The embodiments of the present invention include, as a unit configuredto solve the above-described problems, a unit configured to feed backonly an AC component of a monitor signal of an input current(hereinafter, referred to as an anode current) into a magnetron andcontrol the output of a high voltage power supply. The anode current canbe detected with a resistor and a differential amplifier. Even withrespect to a rapid fluctuation having a short cycle, to which a detectorfor detecting the output of microwave with such a configuration canhardly respond, the output of a high voltage power supply can becontrolled and the fluctuation can be suppressed.

Because a microwave output monitor signal from a microwave outputdetector is fed back in terms of a direct current, a constant microwaveoutput can be obtained as conventionally.

Moreover, with respect to the moding that is the second problem to besolved, a steep current flowing into a magnetron at the occurrence ofmoding can be detected and the output of a high voltage power supply canbe reduced. FIG. 5 shows a waveform of the anode current at theoccurrence of moding. The anode current abruptly increases when themoding occurs, so by detecting this signal and reducing the output ofthe high voltage power supply, the anode current can be suppressed andthe damage to the magnetron and the high voltage power supply can bereduced.

The AC component of the anode current may be detected and a resultingsignal may be output to a host controller as an alarm signal. Even ifthe damage to the magnetron and the high voltage power supply at theoccurrence of moding can be reduced with the microwave output device ofthe present invention, a certain degree of damage is assumed to beadded. Therefore, using the above-described alarm signal, it is possibleto urge a user to exchange or repair the magnetron and the high voltagepower supply according to the number of occurrences of moding.

For the parasitic oscillation that is the third problem to be solved, aswith the case of the above-described moding, the AC component of theanode current is detected and a resulting signal is output to a hostcontroller as an alarm signal. At the occurrence of a parasiticoscillation, as described above, a problem arises that the measurementresult of a microwave output detector is affected and as a result theoutput of microwave will shift. Therefore, in the plasma processingapparatus and the like, the processing needs to be stopped, and thus bydetecting the AC component of the anode current and outputting aresulting signal to a host controller as an alarm signal, the processingcan be adequately stopped at the occurrence of a parasitic oscillation.

As an alternative unit configured to solve the above-described problems,the output of a high voltage power supply has been conventionallycontrolled by a difference between an output setting signal and amicrowave output monitor signal, while in the present invention, theoutput of a high voltage power supply is controlled after calculating adifference between an output setting signal and a microwave outputmonitor signal and then calculating a difference between the abovedifference and a monitor signal of the anode current.

A plasma processing apparatus or a microwave output device having such aconfiguration can control the output of a high voltage power supply evenwith respect to a rapid fluctuation, to which a microwave outputdetector can hardly respond, and suppress the fluctuation, by adding amonitor signal of an anode current in controlling the output of the highvoltage power supply.

Moreover, because the output of the high voltage power supply iscontrolled so that eventually the difference between the output settingsignal and the microwave output monitor signal from the microwave outputdetector becomes zero or becomes a value almost approximated to zero, astable microwave output can be obtained.

Embodiment 1

Hereinafter, embodiments of the present invention will be describedusing the accompanying drawings. FIG. 1 is a vertical cross-sectionalview schematically showing an outline of the configuration of a plasmaprocessing apparatus according to an embodiment of the presentinvention.

The plasma processing apparatus of the embodiment supplies microwaveinto a processing chamber inside a vacuum container to form plasma, andetches a film structure in an upper surface of a substrate-like sample,such as a semiconductor wafer, arranged inside the processing chamber,using this plasma. In particular, in the embodiment, a magnetic fieldfrom a magnetic field generator, such as a solenoid coil, is suppliedinto the processing chamber together with an electric field ofmicrowave, and a processing gas introduced into the processing chamberis excited by ECR (electron cyclotron resonance).

A plasma processing apparatus 100 of the embodiment shown in FIG. 1 isroughly divided into: a vacuum container 101 having a processing chamber122 arranged thereinside; an electromagnetic field supply unitconfigured to supply an electric field or a magnetic field for formingplasma inside the processing chamber 122, the electromagnetic fieldsupply unit being arranged above the vacuum container 101; and anexhaust unit including a vacuum pump 103, such as a turbo-molecularpump, for exhausting gas and/or plasma particles inside the processingchamber 122 and decompressing the inside, the exhaust unit beingarranged under the vacuum container 101. A microwave output deviceaccording to the embodiment constitutes the electromagnetic field supplyunit.

The vacuum container 101 is a metal container with a cylindrical sidewall having the cylindrical processing chamber 122 inside thecylindrical side wall. Although not illustrated, the side wall of thevacuum container is grounded and set to a predetermined electricpotential.

In a circular upper end portion of the cylindrical side wall of thevacuum container 101, there is placed and arranged a microwavetransmission member 106, i.e., a disc made of dielectrics, such asquartz, through which an electric field can transmit. A seal memberarranged between the circular upper end portion and the microwavetransmission member 106 is sandwiched by these, and hermetically sealsbetween the processing chamber 122 and the atmosphere that is at anatmosphere pressure of the outside. The upper portion of the microwavetransmission member 106 constitutes the electromagnetic field supplyunit, and is a portion where microwave propagates toward the processingchamber 122.

The electromagnetic field supply unit includes: a cylindrical structure,such as a waveguide 102, inside which microwave propagates; and aportion being arranged in the cylindrical structure and adjusting theformation and propagation of microwave. At one end of a portionconstituting an upper portion of the waveguide 102, the portion wherethe axis of a tube extends in the horizontal direction, a magnetron 7oscillating and forming microwave is arranged. The magnetron 7 iselectrically coupled to a high voltage power supply 10, and excitesmicrowave by a high voltage applied from the high voltage power supply10.

The excited microwave propagates and travels inside the upper portion ofthe waveguide 102 and along the axis direction extending in thehorizontal direction (the horizontal direction in the view), and theoutput, phase, and the like of the excited microwave are adjusted by anisolator 113 and a microwave automatic matching box 112, which aresequentially arranged along the travelling direction of microwave in ahorizontal portion of the waveguide 102, and the excited microwavereaches the end of the horizontal portion. Note that, in the embodiment,between the isolator 113 and the microwave automatic matching box 112, amicrowave output detector 8 for detecting the output of microwavepropagating inside the waveguide 102 is arranged.

The other end of the horizontal portion is coupled to a portion that isa lower portion of the waveguide 102, the portion where the axis of thetube extends in the vertical direction. The horizontal portion of theupper portion of the waveguide 102 has a rectangular cross section,while the portion extending in the vertical direction is a cylindricalportion having a circular cross section. The cylindrical portion has acircularly-polarized wave generator 121, which rotates, with respect tothe travelling direction, an electric field of microwave traveling fromthe above toward the bottom, and forms a circularly-polarized wave,arranged thereinside. Furthermore, the bottom end of thecircularly-polarized wave generator 121 is a tubular portion having acylindrical shape with the same diameter as that of the cylindricalportion of the vacuum container 101, and is connected to a cavityresonator 123 that causes the microwave propagated into a cylindricalspace to resonate in a specific mode.

To the center portion of the upper surface of a cylindrical metal membersurrounding the space inside the cavity resonator 123, the bottom end ofthe waveguide 102 is connected, and the inside of the cavity resonator123 and the inside of the waveguide 102 are connected to each other.Moreover, the bottom of the cylindrical space inside the cavityresonator 123 is constituted by the upper surface of the microwavetransmission member 106. At least a part of the microwave introducedinto the cylindrical cavity portion 123 is reflected inside acylindrical space between the bottom constituted by the microwavetransmission members 106 and the ceiling surface made from a metalmember constituting the cylindrical cavity portion 123, and reciprocatesand resonates to form an electric field of a specific mode.

The electric field of microwave set to a specific mode in this manner isintroduced into the processing chamber 122 through the microwavetransmission member 106. The vacuum container 101 is connected to anon-illustrated gas supply line through which a processing gas passes,and the processing gas is supplied into the processing chamber 122through a plurality of through-holes that are pre-formed in the centerof a non-illustrated circular shower plate arranged on the lower surfaceside of the microwave transmission member 106.

Moreover, in a portion that is an outer periphery of the cylindricalportion of the vacuum container 101 or the side wall of the cavityresonator 123, the portion surrounding the above-described cylindricalportion or side wall, or in a portion above the cavity resonator 123,the portion surrounding the waveguide 102, a magnetic field coil 104,such as a solenoid coil, is arranged and forms a magnetic field by a DCpower supplied. The static magnetic field excited by the magnetic fieldcoil 104 and the electric field of microwave create an interaction byECR, and the atoms and molecules of the processing gas supplied from theabove into the processing chamber 122 are excited to form plasma 107inside the processing chamber 122.

Under the processing chamber 122, there is arranged a wafer stage 109,i.e., a sample stage, on the top surface of which a wafer 108 to beprocessed is placed and held. Inside the wafer stage 109, there isarranged an electrode, to which a high-frequency electric power isapplied from an RF bias power supply 110. The high-frequency electricpower is for forming a bias potential above the wafer 108 mounted in thetop surface of the wafer stage 109 and thereby promoting anisotropyprocessing of a film structure for constructing a circuit ofsemiconductor devices pre-formed in the top surface of the wafer 108.

The inside of the processing chamber 122 is supplied with a processinggas that is introduced from the shower plate or an inert gas that isintroduced instead of the processing gas while the processing is notimplemented. At the same time, the inside of the processing chamber 122is exhausted by the operation of a vacuum pump 109 connected to anopening arranged at a lower part of the processing chamber 122. By thebalance between the above-described supply and exhaust, the inside ofthe processing chamber 122 is decompressed and maintained at thepressure of a predetermined value. For example, the pressure inside theprocessing chamber 122 during processing is maintained at several Pa orless, but it is maintained at several tens Pa to approximately 100 Pawhile the processing is not carried out.

Note that, the operation of the magnetron 7, the magnetic field coil104, the high voltage power supply 10, the RF bias power-supply 110, andthe like of the plasma processing apparatus of the embodiment isadjusted by a command signal transmitted from a controller that iscoupled thereto by a communication unit. In the embodiment, a hostcontroller 21 is arranged, the host controller 21 receives, via aninterface, a signal output from a unit, such as the microwave outputdetector 8, configured to detect the state of the operation of theplasma processing apparatus 100, and an arithmetic logical unit,according to a received result, reads a software stored in an internalstorage device, calculates a command signal using an algorithm, andtransmits the same via the interface.

In the embodiment, a microwave output monitor signal 13 that is a signalindicative of the value of a microwave output output from the microwaveoutput detector 8 is input to the high voltage power supply 10, and istransmitted to the host controller 21 as the signal of a microwaveoutput 14. In the host controller 2, the microwave output monitor signal13 is compared with an output command value 11 which the host controller21 calculated, and according to this result, the output of the highvoltage power supply 10 is adjusted, thereby the output of the microwavefrom the magnetron 7 is adjusted so as to approaches the output commandvalue 11. Moreover, in the high voltage power supply 10, only the ACcomponent of the anode current monitor signal is fed back to control thehigh voltage output.

Moreover, the high voltage power supply 10 transmits an alarm signal 18,which is obtained by detecting the AC component of the anode currentmonitor signal, to the host controller 21. Upon receipt of the alarmsignal 18, the host controller 21 regards this as the occurrence ofmoding or a parasitic oscillation, and stops a plasma etching process ofthe wafer 108 and reports this fact to a user.

FIG. 2 shows the configuration of the microwave output device accordingto the embodiment. FIG. 2 is a block diagram schematically showing theconfiguration of the microwave output device of the plasma processingapparatus shown in FIG. 1.

The microwave output device 105 shown in FIG. 2 includes the magnetron7, the microwave output detector 8, the high voltage power supply 10,and the host controller 21 shown in FIG. 1, and a filament power supply20. The microwave output device 105 is supplied with an electric powerby the high voltage power supply 10 being electrically coupled to acommercial AC power supply.

The electric power from an AC power supply input 1 is input to a primaryrectification smoothing circuit 2 constituting the high voltage powersupply 10, and is also input to the magnetron 7 through a switchingcircuit 3, a boosting transformer 4, a secondary rectification smoothingcircuit 5, and an anode current detection circuit 6 constituting thehigh voltage power supply 10. The magnetron 7 forms microwave at anoutput corresponding to the electric power from the high voltage powersupply 10.

The output of the formed microwave is detected by the microwave outputdetector 8. The output from the microwave output detector istransmitted, so to speak “fed back”, as the microwave output monitorsignal 13 to the high voltage power supply 10 via a communication unitin order to be used in adjusting the output of the high voltage powersupply 10.

The microwave output monitor signal 13 is input to an error amplifier 9inside the high voltage power supply 10, and is compared, in the erroramplifier 9, with an output command signal 11 indicative of a settingvalue transmitted from the host controller 21. An output control signal15 set to a value corresponding to a difference between the microwaveoutput monitor signal 13 and the output command signal 11 is transmittedto the switching circuit 3 from the error amplifier 9. The output of thehigh voltage power supply 10 is adjusted by the operation of theswitching circuit 3 being adjusted according to the output controlsignal 15.

The above-described configuration and operation are the same as those ofthe related art, however in the embodiment, inside the high voltagepower supply 10, the anode current monitor signal 12 that is an outputfrom the anode current detection circuit and indicates the anode currentvalue is input to the error amplifier 9 via the AC component detectioncircuit 16. In the embodiment, the AC component detection circuit 16 hasa relatively simple configuration by employing a circuit having acondenser coupled in series as shown in FIG. 6.

FIGS. 4A and 4B are views showing an anode current waveform of a relatedart microwave output device and the microwave output device of theembodiment, respectively. In particular, FIGS. 4A and 4B are graphsshowing an example of the anode current by the microwave output deviceaccording to the related art and the microwave output device accordingto the embodiment shown in FIG. 2, respectively.

These views show the magnitude value of the anode current as an outputof the microwave output device. In the value of the output of the anodecurrent of the microwave output device of the related art shown in FIG.4A, a ripple is produced, the magnitude value of which increases anddecreases with a change in time, at a short cycle, e.g., 8.3 ms in thisexample. With respect to the up and down in the output having such ashort cycle, when the response to detect this change is slow, an outputcommand signal capable of reducing such increase and decrease in thevalue cannot be transmitted, and thus the output from the magnetron 7will increase and decrease by reflecting a fluctuation in the value ofthe anode current having a short cycle.

In the embodiment, the AC component of the anode current detected in theanode current detection circuit 6 is detected by the AC componentdetection circuit 16, and the resulting output is input to the erroramplifier 9 together with the output detected by the microwave detector8. In the error amplifier 9. the output command signal 11 input from thehost controller 21 is compared with the microwave output monitor signal13 from the microwave output detector 8 plus the AC component of theanode current monitor signal 12, and an output signal according to thisdifference is transmitted to the switching circuit 3.

An example of the anode current adjusted in this manner in the microwaveoutput device of the embodiment is shown in FIG. 4B. In this view, the120 Hz ripple generated in the microwave output device in the relatedart is suppressed in the microwave output device according to theembodiment and is set to a more constant and approximated value.

In the embodiment, such an AC component of the anode current, i.e., afluctuation having a relatively short cycle of the anode current, isinput to the error amplifier 9 as an error, and is input as a signal forcorrecting the output of the switching circuit 3, thereby responding tothe fluctuation having a short cycle of the anode current that isreflected as the microwave output of the magnetron 7, so that the anodecurrent can be set close to a desired value and set close to a moreconstant value. Therefore, the output from the high voltage power supply10 can be adjusted and output to the magnetron 7, and the output of themagnetron 7 can be stabilized.

Variant 1

A variant of the microwave output device is described using FIG. 3. FIG.3 is a block diagram showing a variant of the microwave output deviceaccording to the embodiment shown in FIG. 1.

In the variant, in addition to the configuration of the embodiment shownin FIG. 2, a detection circuit 17 is arranged inside the high voltagepower supply 10, and the output from the detection circuit 17 istransmitted to a host controller 21 as an alarm signal 18. In thevariant, by inputting to the detection circuit 17 the AC component ofthe anode current that is the output of the AC component detectioncircuit 16, a fluctuation in the anode current generated at theoccurrence of moding or a parasitic oscillation is output to the hostcontroller 21 as the alarm signal 18. Note that the detection circuit 17can be easily realized with a circuit using a diode and a condenser asshown in FIG. 7.

The host controller 21 that received the alarm signal 18 transmits asignal for stopping the operation of the magnetron 7 or the high-voltageline 10, thereby stopping the microwave output device. Moreover, it alsotransmits a signal for stopping the output of the RF bias power supply110 and the output of the magnetic field coil 104 to eliminate theplasma 107 and at the same time reports the abnormality and the stop ofthe operation of the plasma processing apparatus 100 to a user.

Variant 2

Using FIG. 8, another variant of the embodiment shown in FIG. 2 isdescribed. FIG. 8 is a block diagram schematically showing anothervariant of the microwave output device according to the embodiment shownin FIG. 2.

The variant differs from the embodiment shown in FIG. 2 in that theoutput command signal 11 transmitted from the host controller 21 and thesignal output from the microwave output detector 8 are input to theerror amplifier 9 and a difference signal output from the erroramplifier 9 is input to an error amplifier 22 together with the anodecurrent monitor signal 12 and an output obtained as a result ofcomparing the difference signal output from the error amplifier 9 withthe anode current monitor signal 12 is output to the switching circuit3. That is, a difference signal between the signal output from the anodecurrent error amplifier 22 and a signal indicative of a differencebetween the output command signal 11 and the actually-output microwaveoutput is output to the switching circuit 3 as the output control signal15, and the output of the high voltage power supply 10 is adjusted.

Also in this variant, the high voltage power supply 10 may include thedetection circuit 17 shown in FIG. 3 that transmits the alarm signal 18to the host controller 21.

Also in such a configuration, as with the embodiment of FIG. 2, theoutput from the high voltage power supply 10 is adjusted so as to reduceits fluctuation corresponding to a fluctuation having a short cycle inthe anode current, the ripple in the output of the anode current that isthe problem in the related art is suppressed, and the output of theanode current is set to a more constant and approximated value.Therefore, the output of the high voltage power supply 10 can be broughtclose to a desired value and brought close to a more constant value, andthe output of the magnetron 7 can be stabilized.

According to the above embodiment and variants, because the output ofmicrowave is stabilized, the characteristics, such as the electricpotential and distribution, of the plasma formed in a processing chamberinside a vacuum container become more stable, so that a plasmaprocessing apparatus or a microwave output device capable of improvingthe accuracy and/or repeatability of wafer processing can be provided.

It should be further understood by those skilled in the art thatalthough the foregoing description has been made on embodiments of theinvention, the invention is not limited thereto and various changes andmodifications may be made without departing from the spirit of theinvention and the scope of the appended claims.

1. A plasma processing apparatus that forms plasma inside a processingchamber using microwave formed by a magnetron and processes a waferarranged inside the processing chamber, the plasma processing apparatuscomprising: a high voltage power supply for supplying a high voltagepower to the magnetron; and a detector for detecting a microwave outputfrom the magnetron, wherein based on a result of comparing a signal,which is obtained by adding an output from the detector to an ACcomponent of a current detected from an output of the high voltage powersupply, with a setting value of the output of the high voltage powersupply, the output of the high voltage power supply is adjusted.
 2. Theplasma processing apparatus according to claim 1, wherein based on aresult of comparing a signal, which is obtained by adding an output fromthe detector to an AC component of an anode current output from the highvoltage power supply, with a setting value of an output of the highvoltage power supply, the output of the high voltage power supply isadjusted.
 3. A plasma processing apparatus that forms plasma inside aprocessing chamber using microwave formed by a magnetron and processes awafer arranged inside the processing chamber, the plasma processingapparatus comprising: a high voltage power supply for supplying a highvoltage power to the magnetron: and a detector for detecting a microwaveoutput from the magnetron, wherein based on a result of comparing asignal, which is obtained as a result of comparing an output from thedetector with a setting value of an output of the high voltage powersupply, with a signal indicative of a value of a current detected fromthe output of the high voltage power supply, the output of the highvoltage power supply is adjusted.
 4. The plasma processing apparatusaccording to claim 1, wherein a signal obtained by detecting an ACcomponent of a current from an output of the high voltage power supplyis output as an alarm signal.
 5. A microwave output device used for aplasma processing apparatus that forms plasma inside a processingchamber using microwave formed by a magnetron and processes a waferarranged inside the processing chamber, the microwave output devicecomprising: a high voltage power supply for supplying a high voltagepower to the magnetron; and a detector for detecting a microwave outputfrom the magnetron, wherein based on a result of comparing a signal,which is obtained by adding an output from the detector to an ACcomponent of a current detected from an output of the high voltage powersupply, with a setting value of the output of the high voltage powersupply, the output of the high voltage power supply is adjusted.
 6. Themicrowave output device according to claim 5, wherein based on a resultof comparing a signal, which is obtained by adding an output from thedetector to an AC component of an anode current output from the highvoltage power supply, with a setting value of an output of the highvoltage power supply, the output of the high voltage power supply isadjusted.
 7. A microwave output device used for a plasma processingapparatus that forms plasma inside a processing chamber using microwaveformed by a magnetron and processes a wafer arranged inside theprocessing chamber, the microwave output device comprising: a highvoltage power supply for supplying a high voltage power to themagnetron; and a detector for detecting a microwave output from themagnetron, wherein based on a result of comparing a signal, which isobtained as a result of comparing an output from the detector with asetting value of an output of the high voltage power supply, with asignal indicative of a value of a current detected from the output ofthe high voltage power supply, the output of the high voltage powersupply is adjusted.
 8. The microwave output device according to claim 5,wherein a signal obtained by detecting an AC component of the currentfrom the output of the high voltage power supply is output as an alarmsignal.